The second dose is needed for maximum protection.
Princeton University is offering booster shots for students and staff who received the meningitis B vaccine last December.
The second dose will be available from Monday through Thursday at the school's Frist Campus Center. It's available to undergraduate students, graduate students living on campus and staff members with certain illnesses.
Thousands chose to get the vaccine for the B strain of the meningitis bacteria. The vaccine is approved for use in Europe, Australia and Canada but is not yet approved for general use in the United States.
The vaccinations were given in December as part of the university's effort to halt an outbreak.
People who only received one dose of the vaccine have an increased risk of getting meningitis, because the protection provided by the first dose declines over time.
Click here for more news from New Jersey, Pennsylvania and Delaware.